The present invention relates generally to optical wavelength division multiplexers/demultiplexers (WDM). More specifically, the present invention relates to optical multiplexers/demultiplexers wherein the device incorporates two primary components which are adhesively bonded to form an optic module. The present invention provides specially designed adhesive overflow channels with dams formed on the upper surface of a molded coupling module to which an optical block is adhesively mounted. The. invention facilitates the use of low viscosity adhesive which in turn reduces the thickness of the adhesive bond between the major pieces, thereby achieving a tighter bond and better alignment of the optics.
The present invention is particularly effective in achieving a tighter and more parallel bond between the optical block and molded coupling module components in the multiplexer/demultiplexer design shown and described in U.S. application Ser. No. 09/347,490, which is incorporated by reference herein as though set forth in full. The design shown in Ser. No. 09/347,490 incorporates a pattern of relief cuts wherein each relief cut extends through the exterior side wall of the molded coupling module. Those relief cuts did not allow the use of relatively low viscosity adhesive being used to join the primary two components of the device together, because the low viscosity adhesive would drip down the sides of the module, potentially contaminating the optical pathway extending through the lower surface of the module. Using a high viscosity adhesive limits the closeness of the adhesive bond between the two components and limits the degree of parallelism between those components achievable by the adhesive bond.
The present invention provides a new modified form of adhesive overflow channel which allows the use of a much lower viscosity adhesive. The use of the low viscosity adhesive reduces the thickness of the adhesive joint, increasing the degree of parallelism between the lower surface of the optical block and the upper surface of the molded coupling module. Increasing the parallelism between those components significantly enhances the optical alignment and operational characteristics of the assembled multiplexer/demultiplexer.
A primary object of the invention is to provide an improved design for achieving a very thin adhesive bond between the two primary components of an optical multiplexer/demultiplexer, enhancing the optical alignment characteristics of the assembled device.
A further object of the invention is to provide one or more adhesive overflow channels between an upper and lower optical component wherein the performance of the assembled device is enhanced by achieving the thinnest possible adhesive bond between components.
Another object of the invention is to provide adhesive overflow channels wherein each channel has a dam formed near the outermost edge of the lower optical component to facilitate the use of low viscosity adhesive and to prevent the adhesive from spilling over the outermost edges of the optical component and potentially contaminating the optical pathway of the WDM.
Other objects and advantages will become apparent from the following description and the drawings wherein: